Defensive publication



DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Apr. 11, 1968, 849 O.G. 1221. Identification is by serial number of the application and the heading indicates the number of pages of specification, including claims, and of sheets of drawing contained in the application as originally filed. The file of this application is available to the public for inspection; reproduction may be purchased for 130 cents per sheet.

Applications published under the Defensive Publication Program have not been examined as to the merits of alleged invention. The Patent Ofllce makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED MARCH 18, 1969 647,320 POLYMER PREPARED BY THE HYDROLYSIS 0F AROMATIC POLYIMIDES AND CONVERSION OF THE RESULTING POLYAMIDE-ACID LINKAGES TO FORM AROYLOXYPROPANESULFONATE DYE SITES Robert Samuel Irwin, Newark, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed June 20, 1967. Published Mar. 18, 1969 Class 855 No Drawing. 36 Pages Specification Processes for (1) hydrolysis of imide linkages of arcmatic polyimides to corresponding polyamide-acid linkages by reaction with barium hydroxide or strontium hydroxide and (2) conversion of the resultant polyamideacid linkages to form dyeable aroyloxypropanesulfonate dye sites; and polymers produced by said processes. 

